Novel Online Diagnostic Analysis for In-Flight Particle Properties in Cold Spraying
In cold spraying, powder particles are accelerated by preheated supersonic gas stream to high velocities and sprayed on a substrate. The particle velocities depend on the equipment design and process parameters, e.g., on the type of the process gas and its pressure and temperature. These, in turn, affect the coating structure and the properties. The particle velocities in cold spraying are high, and the particle temperatures are low, which can, therefore, be a challenge for the diagnostic methods. A novel optical online diagnostic system, HiWatch HR, will open new possibilities for measuring particle in-flight properties in cold spray processes. The system employs an imaging measurement technique called S-PTV (sizing-particle tracking velocimetry), first introduced in this research. This technique enables an accurate particle size measurement also for small diameter particles with a large powder volume. The aim of this study was to evaluate the velocities of metallic particles sprayed with HPCS and LPCS systems and with varying process parameters. The measured in-flight particle properties were further linked to the resulting coating properties. Furthermore, the camera was able to provide information about variations during the spraying, e.g., fluctuating powder feeding, which is important from the process control and quality control point of view.
Keywordscold spraying diagnostics in-flight properties particle size particle velocity
The work has been done within DIMECC Ltd. and its HYBRIDS program. The authors gratefully acknowledge the financial support from Tekes (Finnish Funding Agency for Technology and Innovation) and the participating companies. Also, the authors would like to thank Mr. Mikko Kylmälahti, of Tampere University of Technology, for spraying experiments and M.Sc. Juha Lagerbom, of VTT (Finland), for measuring particle size distributions by laser diffraction technique.
- 1.V. Champagne, Ed., The Cold Spray Materials Deposition Process: Fundamentals and Applications, Woodhead Publishing Ltd., Cambridge, 2007, p 362Google Scholar
- 2.A. Papyrin, V. Kosarev, S. Klinkov, A. Alkimov, and V. Fomin, Cold Spray Technology, 1st ed., Elsevier, Netherlands, 2007, p 328Google Scholar
- 7.M. Jeandin, H. Koivuluoto, and S. Vezzu, 4 Coating Properties, Modern Cold Spray, Materials, Process, and Applications ed. by J. Villafuerte (Springer, 2015), p 107-224Google Scholar
- 9.L. Pouliot, 8 Quality Assurance, Modern Cold Spray, Materials, Process, and Applications ed. by J. Villafuerte, (Springer, 2015), p 303-316Google Scholar
- 14.H. Koivuluoto, Microstructural Characteristics and Corrosion Properties of Cold-Sprayed Coatings, Doctoral Thesis, Tampere University of Technology, Tampereen Yliopistopaino Oy, Tampere, 2010Google Scholar
- 15.T. Hussain, S. Yue, and C.-J. Li, 3 Characteristics of Feedstock Materials, Modern Cold Spray, Materials, Process, and Applications ed. by J. Villafuerte, (Springer, 2015), p 73-106Google Scholar
- 17.Edmund Optics, Inc.: https://www.edmundoptics.com/resources/application-notes/imaging/advantages-of-telecentricity/, June 2017
- 18.H. Koivuluoto, A. Coleman, K. Murray, M. Kearns, and P. Vuoristo, High-Pressure Cold Sprayed (HPCS) and Low Pressure Cold Sprayed (LPCS) Coatings Prepared From OFHC Cu Feedstock—Overview From Powder Characteristics to Coating Properties, J. Therm. Spray Technol., 2012, 21(5), p 1065-1075CrossRefGoogle Scholar
- 21.M. Gauthier, Engineering Data for Metals and Alloys, Metals Handbook Desk Edition, ASM International, 1998, p 64-84Google Scholar
- 22.T. Kairet, G. Di Stefano, M. Degrez, F. Campana, and J.-P. Janssen, Comparison Between Coatings from two Different Copper Powders: Mechanical Properties, Hardness and Bond Strength, Thermal Spray 2006: Building on 100 Years of Success, ed. by B. Marple, M. Hyland, Y.-C. Lau, R. Lima, and J. Voyer, May 15-18, 2006, Seattle, Washington, USAGoogle Scholar